1. Field of the Invention
The present invention relates to a superabrasive grain setting apparatus for mounting superabrasive grains on a manufacturing mold which is used in arranging superabrasive grains on a grinding surface of a grinding tool such as grinding wheel, truing tool, dressing tool or the like in the manufacturing process for such a grinding tool.
2. Discussion of the Related Art
In the manufacturing of a grinding tool such as grinding wheel, truing tool, dressing tool or the like, it is often the case that a grinding surface of the grinding tool are formed by the use of superabrasive grains such as diamond, CBN (Cubic Boron Nitride) or the like. In this case, the grinding tool should have superabrasive grains arranged uniformly so that the grinding surface is able to grind a workpiece without any local imbalance in grinding operation. To this end, in manufacturing grinding tools, there is utilized a so-called “grain transfer method”, wherein superabrasive grains arranged on an internal surface of a female-type manufacturing mold are transferred onto an external grinding surface of a male-type grinding tool, while superabrasive grains arranged on an external surface of a male-type manufacturing mold are transferred onto an internal grinding surface of a female-type grinding tool. It has been a practice that an abrasive grain layer is formed on a mold surface of a manufacturing mold which is used to form the grinding surface of the grinding tool, by arranging superabrasive grains in the same pattern or arrangement as they should be planted in the grinding surface of the grinding tool. The setting of the superabrasive grains on the manufacturing mold is a work needing preciseness and heretofore, has been performed by hand craft of a skilled worker. Then, because the work is the routine repetition of precision job steps, and for higher efficiency and higher productivity, there has been conceived a superabrasive grain setting robot 100 shown in FIG. 21. In the superabrasive grain setting robot 100, a suction nozzle 102 is provided to be movable by a moving mechanism (not shown) in the horizontal direction as well as in the vertical direction, and a carbon mold CW being a manufacturing mold is supported by a grip mechanism (not shown) to be rotatable about the axis thereof and to be adjustably placed upward and downward at a desired inclination angle. In this prior art system, first of all, the carbon mold CW is inclined upward to place a mounting surface of the carbon mold CW horizontally, as shown in FIG. 22, then the suction nozzle 102 is horizontally advanced to place a grain D of superabrasive on the extreme end thereof right over the mounting surface, as shown in FIG. 23, and the suction nozzle 102 is lowered vertically to mount each grain D of superabrasive on the mounting surface, as shown in FIG. 24.
The carbon mold CW for a grinding tool may be small in the opening diameter of a hole formed in the carbon mold CW or may have as a mounting surface a steep inclination taper surface, a tiny rounded surface, a deep groove or recess or the like in dependence on a shape of the tool to be manufactured. However, in the known superabrasive grain setting robot system, it is unable to simultaneously perform an inclination movement of the carbon mold CW and an advance movement of the suction nozzle 102, and it is also unable to perform a moving operation of the suction nozzle in an oblique downward direction. For this reason, as shown in FIG. 25 for example, when the carbon mold CW is inclined and then the suction nozzle 102 is advanced straight, interference with the mounting operation of the suction nozzle 102 takes place sometime wherein the suction nozzle 102 hits an end surface of the carbon mold CW or any other portion than the extreme end of the suction nozzle 102 comes into contact with a projecting part of the carbon mold CW. Therefore, the known setting robot system is unable to work for carbon molds CW complicated in the shape of a surface which should have superabrasive grains D arranged thereon, and sometime, cannot perform the setting work. This naturally results in the need for human's hand as separate job step in performing the setting on portions on a carbon mold which are impossible for the known setting robot system to do so.